The present invention relates to devices for fastening guardrails to building elements.
Guardrails typically comprise spaced posts connected by a top rail and a bottom rail forming structural elements and by filling elements limiting the size of the openings between the structural elements to a value such that there is no risk of falling. The filler elements may consist of parallel vertical bars, whose maximum spacing is fixed by standards.
A guardrail is generally secured to a building element, for example to a concrete slab. Conventional fastening devices belong to two types. A first approach consists of bedding stiffening posts designed to give sufficient bending strength in building elements, generally in the upper or front vertical surface of a slab. Another solution consists of securing anchor plates in the building and engaging the stiffening posts into the plates.
The first approach requires considerable labor time. The second approach results in the bottom rail being spaced from the building element by a space at least equal to the thickness of the plate, which should be substantial for reasons of mechanical strength. Consequently, there remains a gap whose width is sufficient to allow articles of a size such that their fall can endanger person and damage property, subsists, either above the slabs, or in front of the latter if the plate is secured to a slab front surface.
It is an object of the invention to provide an improved fastening device which is easily secured and assembled and makes it possible to locate the bottom rail at a height above the slab which is freely selected and may be quite small.
The device for fastening a guardrail including stiffening posts connected by a top rail and a bottom rail to a building element comprises an anchor plate constructed to be permanently secured to the building element and a base plate having a bearing surface cooperating with the anchor plate. The base has fastening means for a post; the amount of horizontal projection of the fastening means with respect to the anchor plate and the rest of the base plate is sufficient to permit the lower surface of the post to contact the building element and the bottom rail to be placed at any position between the building element and the fastening means. The fastening means may comprise a collar unitary with the base plate and through which the post projects and a wedge member for locking the post in the collar.
The invention is of particular advantage when the posts and rails are formed by light alloy sectional elements as described for instance in U.S. Pat. No. 3,411,752 (BOS). The stiffening posts will then generally be hollow tubes with a rectangular cross-section. Each collar can be formed with a passage for a post of a size corresponding to that of the post, having three vertical guiding surfaces and an inclined surface. The locking member for the post will then be a wedge insertable between the inclined surface and the post and whose force of insertion is adjustable by threaded means, such as a screw of which the head is retained in a chamber formed in the wedge member and which cooperates with a tapped bush fast with the stiffening post. Filler elements will advantageously be placed between the stiffening posts. These elements can be parallel bars or plates, for example of translucent plastics material or reinforced glass.
The invention will be better understood from a consideration of the particular embodiment given by way of example.